mlx4: Fixing wrong error codes in communication channel

The communication channel is HW interface from PF point of view
So the command return status should be stored as HW error code
and only then translated to errno values.

Reporetd-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>